<p><i>alias:</i> <b>atConnectionRatio</b></p>
<p>Move and auto-orient the subelement to the point at a given ratio of the connection total length. It accepts a number in the <code>[0,1]</code> range. It is valid only within the LinkView context.</p>

<pre><code>link.attr('rectSelector', { atConnectionRatio: .5, width: 10, height: 10, fill: 'red' });
link.attr('rectSelector', { atConnectionRatioKeepGradient: .5, width: 10, height: 10, fill: 'red' });</code></pre>
